Fuel cells are used as an electrical power source in many applications. In particular, fuel cells are proposed for use in automobiles to replace internal combustion engines. A commonly used fuel cell design uses a solid polymer electrolyte (“SPE”) membrane or proton exchange membrane (“PEM”) to provide ion transport between the anode and cathode. In proton exchange membrane type fuel cells, hydrogen is supplied to the anode as fuel and oxygen is supplied to the cathode as the oxidant. The oxygen can either be in pure form (O2) or air (a mixture of O2 and N2). PEM fuel cells typically have a membrane electrode assembly (“MEA”) in which a solid polymer membrane has an anode catalyst on one face, and a cathode catalyst on the opposite face.
Modern fuel cell vehicles store hydrogen in pressure vessels with pressures up to 700 bar. Typically, these vessels are made of a liner material that functions as a barrier to gas diffusion. The liner is typically surrounded by a matrix of carbon fiber layers which are mainly responsible to hold the stress of a 700 bar filled vessel. In some cases, the liner which is a very soft material, delaminates from the fiber compound and buckles to the inside. It is believed that such delamination occurs at around a pressure of zero bar inside the vessel (i.e., an empty vessel). It is also observed that buckling can also occur at higher inner pressures when the delta pressure to the outside is high enough. This is the case when gas diffusing through the liner material is trapped between the compound and the liner. Liner buckling is regarded as a contributor to high stress inside the liner material which then could lead to durability issues and fatigue cracks of the liner material.
Accordingly, there is a need for improved systems for storing pressurized gases for fuel cell applications that provide an online detection method to detect the start of a liner buckling.